Overload releasing device



April 3, 1934. E PA E 1,953,430

' OVERLOAD RELEASING DEV-ICE Filed Jan. 16. 1930 2 Sheets-Sheet 1 nw wmnmmul lllll E. PARRE OVERLOAD RELEASING DEVICE April 3, 1934.

Filed Jan. 16, 1950 2 Sheets-Sheet 2 173062721 071 1274220522 BzY-re,

Patented Apr. 3, 1934 intact) PATENT! OFFICE UNITED STATES The present invention relates to overload releasing devices and refers more particularly to a mechanism adapted to be interposed between a driving and a driven member, which will automatically disengage when the driven member offers a predetermined amount of resistance. The invention will be readily understood from the following detailed description in conjunction with the accompanying drawings,.in which Figure 1 is a side elevational view, of a device embodying the present invention, taken in section on line 1 of Fig. 2;

Fig. 2 is a vertical sectional view taken on line 2 of Fig. 1;

Fig. 3 is a fragmentary plan view showing the manner in which the expanding arms are secured to the crank-member carried by one of the shafts;

Fig. 4 is a fragmentary plan view showing the manner in which the engaging rollers are mounted on the expanding arms; and v Figs. 5 and 6 are side elevational views of modifled forms of expanding arm-members.

Referring more in detail to the drawings, and Figs. 1 to 4 is particular, 10 and 11 designate a pair of shafts mounted in suitable bearings provided in brackets 12 and 13 respectively. The shafts 10 and 11 are preferably mounted on the same axis and their ends are slightly spaced apart.

The hub 14 of a disk 15 is keyed to the shaft 10 by means of a suitable key 16. The disk 15 is provided with an annular flange 17, the inner face of which is provided with suitable engaging means which may comprise one or more depressions 18.

The shaft 10 has keyed to it, by means ofa key 20, a transversely extending arm or crankmember 19. The arm 19 is preferably mounted within the plane defined by the annular flange 17. A pair of arm-members 21 and 22 have one of their ends pivotally secured to the outer end of the crank arm 19. The arm-members 21 and 22 are preferably secured to the end of the crank arm 19 in the manner shown in Fig. 3, i. e. the

ends of the arms being bifurcated and pivoted on a common pin 19 carried by the arm 19. The arms 21 and 22 extend in inverse or opposite directions from the end of thearm 19 and terminate at a point substantially equidistant therefrom,

the free ends of the arms lying in a plane which passes between the side o the shaft 11 opposite the end of the arm 19 and the inner face of the flange 17.

Each of the arms 21 and 22 is provided at an intermediate point thereof with a member for engaging the depressions 18 and the flange 17. This engaging member may suitably comprise a roller 23 rotatably mounted upon a pin 24 carried between a pair of outwardly protruding spaced ears 25 formed on the arms 21 and 22. The ends of the arms 21 and 22 carry between them a suitable expanding means which may comprise a coiled spring 26. The free end of arm 21 is provided with a protruding boss 27 adapted to be engaged by one end of the spring 26, while the free end of the arm 22 is provided with a suitable means for engaging the spring and adjusting the compression thereof. The adjustable means may suitably comprise a nut 28 provided with a protruding boss 29 which extends within the spring 26. ,The nut 28 is threaded upon a stud-bolt 30 carried by the free end of the arm 22. Thus it will be seen that the spring 26 tends to force the free ends of the arms '21 and 22 apart whereby the rollers 23 will be forced against the inner face of the flange 1'1 and into engagement with the depressions 18 therein.

The operation of the device will be apparent from the foregoing description. Let us assume, for example, that the shaftlO is the driving shaft and the'shaft 11 is the driven shaft. Under these conditions, the shaft 10 will drive the shaft 11 so long as the rollers 23 remain in engagement with the depressions 18 in the flange 1'7, the driving force exerted on the arms 21 and 22 being exerted upon the arm 19 and the shaft 11. When the shaft 11 offers a predetermined amount of resistance against rotation, the rollers 23 will roll out of engagement with'the depressions 18 and when out of engagement therewith the anus 21 and 22 will be moved closer together against the force of the spring 26. Each time the rollers 23 engage the depressions 18 they will ride out of them so long as the resistance of the shaft 11 exceeds the predetermined amount.

It will be apparent that the structure is exceedingly simple and the operation of the device may be accurately controlled since it is only necessary to adjust the tension of the single spring member 26. The employment of a single spring betweenthe two arms 21 and 22 and the mounting of the arms 21 and 22 on a common fulcrum point on the crank-arm 19 causes the device to be inherently self-compensating and self-centering, since the expanding engaging means comprising the arms 21 and 22 isfree to move relative to the shaft 11 and arm 19 at the points where it engages the flange depressions 18.

In Fig. 5 there is shown a modified t pe of structure for the expansible flange engaging means. The parts shown in Fig. 5 which are similar to those shown in Figs. 1 to 4 are indicated by the same characters of reference applied to Figs. 1 to 4. A block 35 of para rubber is employed, to press the arms 21 and 22 apart and into engagement with the annular flange 17, instead of the coil metal spring 26 shown in Figs. 1 to 4. The rubber block 35 is carried between a pair of cup-like holders 36 and 37 secured to the free ends of the arms 21 and 22, respectively,

The compression of the block 35 is varied by means of the bolt 38 which has threaded engagement with the free end of arm 22, and the end of the bolt 38 bearing against the bottom of the cup-like holder 37. By employing the rubber block 35 to force the arms 21 and 22 into engagement with the annular flange 1'7, I find that a much greater force may be extended against the arms 21 and 22 than could be extended with a coiled, or other, metal spring member adaptable to the space defined by the free ends of arms 21 and 22, and the shaft 11 and flange 17. Thus a given size releasing unit, employing ;a rubber block, may be successfully used in mechanical operations, the power conditions of which are heavier than those with which the same device can be used when a coiled, or other, metal spring is employed to expand or spread the arms 21 and 22.

In Fig. 6 is shown another modified type of structure. Instead of pivoting the arms to a common point or fulcrum, as illustrated in the embodiment shown in Figs. 1 to 4, a pair of oppositely extending arms 40 and 41 are mounted on a common hub 42 keyed to the shaft 11. The arms 43 and 44 correspond to the arms 21 and 22 already described and have one of their ends pivotally attached to the arms 40 and 41, respec tively. The flange engaging rollers 23 are mounted adjacent the ends of the arms 43 and 44 and the spring member 26 is carried between the arms at points intermediate the rollers 23 and the point of fulcrum of the arms 43 and 44.

It is to be understood that while I have shown and described an embodiment adapted to be directly connected to a pair of shafts, my invention may be employed to connect any type of driving and driven members. For example, the crank 19 and arms 21 and 22 may be keyed to a single shaft and the flanged disk 15 may be mounted on the same shaft for free rotative movement relative thereto. In such an embodiment the periphery of the disk 15.may engage a belt, or it may be provided with teeth for engaging a chain or a gear wheel.

The foregoing detailed description is given for clearness of understanding only, and no unnecessary limitations should be understood therefrom, but the appended claim should be construed as broadly as permissible, in view of the prior art.

I claim:

An overload clutch comprising: a rotatable driving member, a rotatable driven member provided with a circular contacting portion having diametrically opposed notches, a pair of opposed driving arms pivotally connected to said driving member and each having a projection adapted to engage one of a pair of said diametrically opposed notches in the driven member, and common means acting on both of said arms to urge them into yielding engagement with said pair of notches.

EDWIN PARRE. 

